document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=672623>Question 672623</A>: <I><SPAN STYLE=\"word-break: break-all;\"> n(B)=20, n(A^B)=5, n(AvB)=30 find n(A) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #418215 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=418215\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Just to be clear, in this context, A^B means \"set A intersect set B\"\r<BR>\n" );
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document.write( "n(A^B) = n(A) + n(B) - n(AvB)\r<BR>\n" );
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document.write( "5 = x + 20 - 30 \r<BR>\n" );
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document.write( "5 = x - 10\r<BR>\n" );
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document.write( "5+10 = x\r<BR>\n" );
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document.write( "15 = x\r<BR>\n" );
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document.write( "x = 15\r<BR>\n" );
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document.write( "So n(A) = 15 </SPAN>\n" );
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